Ionic "Invalid device state" Error with Xcode 7: Solved

November 17, 2015

I've been working on an Ionic Framework project for a while now. Just recently after I upgraded to Xcode 7, however, I couldn't get a project to install on the iOS simulator. Every time I would build an emulate the project, the process would fail with an "Invalid device state" error. I tried a number of things: rebooting my machine, reinstalling Xcode, etc. What I discovered, however, was the root of this problem had nothing to do with Xcode 7, but instead with file permissions.

Invalid Device State

Often when installing a node project using npm, our system may require use to use sudo to execute the command without error. At some point, however, we may choose to use sudo when it isn't necessary. In the case of the "invalid device state" error, that's likely what's happened, especially if you are using sudo to run the ionic build ios and ionic emulate ios commands. So, when is it appropriate to use sudo when you are building an app with Ionic?

When to use sudo

If you look closely at the error produced when a build fails, you also see an error like this:

no such file or directory, stat '/Users/username/Library/Logs/CoreSimulator/D2FFF2E1-C3D2-4D1A-ABE2-242D3EAEDFC7/system.log'

This was a little odd to me. Even though it told me it didn't exist, I felt like the system really just couldn't see that system.log file. This is when I suspected a permissions problem.

When you use the Ionic Framework Getting Started Guide, you'll notice that node of the ionic commands use sudo. It is perfectly fine (and sometimes necessary) to use sudo with the npm commands, but don't use sudo on the ionic commands.